This is the worst kind of problem to troubleshoot - an intermittent related to environmentals. I think you have a bad electrical connection caused by cold temperatures such as a cracked solder joint...

No one has showed their PLX Organic LED (OLED) as installed in the tachometer by In Your Face Gauges, Inc. Basically, the OLED functions like a small TV screen and you can display whatever you want....

Gee, I have a whole toolbox full of the orange ones, a nice one from my dad's 1968 912, and a real pretty one from my brothers 914, I think it was a 1974. I don't know where the other ones came from...